The present invention relates to a method and apparatus for fusing together the bottom of a tubular container formed of a synthetic resin for a short period of time and with high productivity but with little or no noise during fusing.
In the prior art, synthetic resin tubes which had been charged have been fused together at their bottom by applying ultrasonic waves on the faces to be fused together in a direction perpendicular thereto or parallel therewith.
With the application of ultrasonic vibrations on the faces to be fused together in a direction perpendicular thereto, fusing is impossible, or effected with reduced fusing strength, when the content is deposited onto the faces. In the latter case, a part of the synthetic resin forming the faces to be fused together is powdered and scattered in the content, leading to its deterioration.
With the application of ultrasonic vibration on the faces to be fused together in a direction parallel therewith, on the other hand, the faces to be fused together are burred, resulting in a lowering of quality. Fusing is also effected in an unsatisfactory working atmosphere with unpleasant frictional noise. In addition, a time required for fusing is so long that productivity drops.